When you have received a new crystal, we recommend that you cleanse it of old energies. Make the purification process itself a part of your meditation, be conscious in your movements. Start by gently washing it in water. Place it on a clean cloth or towel in a place where it can then lie and dry.
Charge it with your intentions; take the crystal in your hand, or in both of your hands. Sit comfortably. Close your eyes and take careful deep breaths. Feel what kind of energy the crystal gives you. Then formulate an intention for your crystal. What do you want the crystal to help you with? How do you want the crystal to make you feel? Be as specific as possible. When you are done, take a few breaths to show your crystal gratitude. In order for your crystal to become as powerful as possible, we recommend that you let it rest in the moonlight for a couple of nights. Put it in the window or near the window in a place where the light of the moon reaches it. At full moon and new moon, the moon is extra powerful, so it's always good to recharge your crystals.
PS You don't need to charge all your crystals, they have powers even if you don't set an intention or charge in moonlight. When you hold your crystal for the first time, feel whether you need to clean it or not.
A tip is to occasionally blow the dust away from them if they are standing in front, so that they reach out with their energy to the fullest.
Good luck!